1. Field of Invention
The invention relates to a motor and, in particular, to a motor with a two-direction buffering function.
2. Related Art
With reference to FIG. 1, a conventional motor 1 generally includes a stator 11, a first bearing 121, a second bearing 122, a spring 123, and a rotor 13. The stator 11 has a hole 111. The first bearing 121, the second bearing 122 and the spring 123 are disposed in the hole 111. The first bearing 121 and the second bearing 122 are in touch with the inner wall of the hole 111 and positioned inside the hole 111. Besides, the spring 123 is connected to one side of the second bearing 122. The rotor 13 has a shaft 131, which is disposed in the hole 111, passing through the first bearing 121, the spring 123, and the second bearing 122 in order.
When the motor 1 starts, the electrical field of the coil winding around the stator 11 or the rotor 13 fluctuates to cause variation in the magnetic field. The rotor 13 is driven by the magnetic force to rotate relative to the stator 11. However, at the instant that the motor 1 starts or stops, the rotor 13 is under an abrupt magnetic force. This magnetic force does not only rotate the rotor 13, but often pushes the shaft 131 along the axis. Therefore, the shaft 131 generates an impact on the first bearing 121 or the second bearing 122, and may even cause vibrations between the first bearing 121 and the second bearing 122. This will eventually result in damages to the motor 1 and make it fail.
In the conventional structure, only the spring 123 touches against the second bearing 122 and alleviates the force on it. Thus, the first bearing 121 is still under the above-mentioned impact and may be damaged.
Besides, once the motor 1 is under an external force, such as a hit or a collision, the force will concentrate on the shaft 131. Therefore, the shaft 131 also generates an impact on the first bearing 121 and the second bearing 122. However, the spring 123 can only relieve the external force on the second bearing 122 while the first bearing 121 may still be damaged due to the external force.